Prior self-sealing composite and unitary roofing and siding shingles which generally employ heat and/or pressure sensitive globules, dabs, stripes or bands of adhesive are well known. The adhesive is commonly applied in a predetermined location on the top or under surface of the shingle unit so that, when courses are installed in a typical overlapping relationship, the adhesive on one sheet adheres to the successive shingle in the course. Typical self-sealing shingles of this type are described in U.S. Pat. Nos. 6,083,592; 3,903,340; 3,252,257 and 2,863,405. Since the exposed surfaces of shingles are coated with granules, sand or other weather resistant particles, courses are joined through an adhesive-to-mineral bond. Serious problems due to loss or shifting of the granules and weakening of the bond have resulted from this arrangement which are manifested in wind lift and/or shingle displacement. Also, inordinate time is required to obtain maximum bonding between courses in the present systems.
In order to strengthen the adhesion between courses, double and even triple rows of adhesive have been proposed for coating on the top or bottom surface of the shingle unit. While this solution may reduce damage due to wind lift because of the increased sealing sites, it significantly adds to the expense of the roofing material. Further, these solutions do not address low temperature bonding which under the present practice requires about 15 hours at 135° F. to complete.
Accordingly it is an object of this invention to overcome or minimize the above deficiencies by an inexpensive and commercially feasible bonding system.
Another object is to materially reduce the period of bonding required to unite courses of shingles or shingle components in roofing or siding.
Still another object is to provide a stronger, more durable system of bonding in a roofing or siding installation.
These and other objects and advantages of the invention will become apparent from the following description and disclosure.